From 23e038568a52e3274e1d1f15882ed4f70b282e7f Mon Sep 17 00:00:00 2001 From: John Lapeyre Date: Thu, 27 Jun 2024 05:08:24 -0400 Subject: [PATCH] Implement RGate in Rust (#12662) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * Implement RGate in Rust * Update crates/circuit/src/operations.rs Co-authored-by: Elena Peña Tapia <57907331+ElePT@users.noreply.github.com> * Fix error in decomposition of RGate There is an error in the expression for decomposition of the R gate in the port to Rust. This fixes the error and re-enables the skipped test that failed because of the incorrect expression. * Factor cloning the Param enum in Rust To clone the enum, each variant must be handled separately. This is currently used once, but can be used each time a `Param` is cloned. In case more work needs to be done within match arms, one might choose not to use this function, but rather clone in each of these arms. * Run cargo fmt * Implement and use addition for enum Param This handles `Float` and `ParameterExpression` variants uniformly. --------- Co-authored-by: Elena Peña Tapia <57907331+ElePT@users.noreply.github.com> --- crates/circuit/src/gate_matrix.rs | 13 ++++++ crates/circuit/src/imports.rs | 2 +- crates/circuit/src/operations.rs | 52 +++++++++++++++++++--- qiskit/circuit/library/standard_gates/r.py | 3 ++ qiskit/circuit/quantumcircuit.py | 4 +- 5 files changed, 65 insertions(+), 9 deletions(-) diff --git a/crates/circuit/src/gate_matrix.rs b/crates/circuit/src/gate_matrix.rs index 80fecfb597c6..2a3fcdf88289 100644 --- a/crates/circuit/src/gate_matrix.rs +++ b/crates/circuit/src/gate_matrix.rs @@ -24,6 +24,19 @@ const fn c64(re: f64, im: f64) -> Complex64 { pub static ONE_QUBIT_IDENTITY: [[Complex64; 2]; 2] = [[c64(1., 0.), c64(0., 0.)], [c64(0., 0.), c64(1., 0.)]]; +#[inline] +pub fn r_gate(theta: f64, phi: f64) -> [[Complex64; 2]; 2] { + let half_theta = theta / 2.; + let cost = c64(half_theta.cos(), 0.); + let sint = half_theta.sin(); + let cosphi = phi.cos(); + let sinphi = phi.sin(); + [ + [cost, c64(-sint * sinphi, -sint * cosphi)], + [c64(sint * sinphi, -sint * cosphi), cost], + ] +} + #[inline] pub fn rx_gate(theta: f64) -> [[Complex64; 2]; 2] { let half_theta = theta / 2.; diff --git a/crates/circuit/src/imports.rs b/crates/circuit/src/imports.rs index 632f5b0f5737..bf06685ba53b 100644 --- a/crates/circuit/src/imports.rs +++ b/crates/circuit/src/imports.rs @@ -157,7 +157,7 @@ static STDGATE_IMPORT_PATHS: [[&str; 2]; STANDARD_GATE_SIZE] = [ // CRZGate = 31 ["placeholder", "placeholder"], // RGate 32 - ["placeholder", "placeholder"], + ["qiskit.circuit.library.standard_gates.r", "RGate"], // CHGate = 33 ["qiskit.circuit.library.standard_gates.h", "CHGate"], // CPhaseGate = 34 diff --git a/crates/circuit/src/operations.rs b/crates/circuit/src/operations.rs index d9626b5c7371..e0e93726735d 100644 --- a/crates/circuit/src/operations.rs +++ b/crates/circuit/src/operations.rs @@ -239,7 +239,7 @@ static STANDARD_GATE_NUM_QUBITS: [u32; STANDARD_GATE_SIZE] = [ 1, 1, 1, 2, 2, 2, 3, 1, 1, 1, // 0-9 2, 2, 1, 0, 1, 1, 1, 1, 1, 1, // 10-19 1, 1, 1, 2, 2, 2, 1, 1, 1, 34, // 20-29 - 34, 34, 34, 2, 2, 2, 2, 2, 3, 2, // 30-39 + 34, 34, 1, 2, 2, 2, 2, 2, 3, 2, // 30-39 2, 2, 34, 34, 34, 2, 34, 34, 34, 34, // 40-49 34, 34, 34, // 50-52 ]; @@ -249,7 +249,7 @@ static STANDARD_GATE_NUM_PARAMS: [u32; STANDARD_GATE_SIZE] = [ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, // 0-9 0, 0, 0, 1, 0, 0, 1, 3, 0, 0, // 10-19 0, 0, 0, 0, 2, 2, 1, 2, 3, 34, // 20-29 - 34, 34, 34, 0, 1, 0, 0, 0, 0, 3, // 30-39 + 34, 34, 2, 0, 1, 0, 0, 0, 0, 3, // 30-39 1, 3, 34, 34, 34, 0, 34, 34, 34, 34, // 40-49 34, 34, 34, // 50-52 ]; @@ -514,7 +514,12 @@ impl Operation for StandardGate { _ => None, }, Self::CRXGate | Self::CRYGate | Self::CRZGate => todo!(), - Self::RGate => todo!(), + Self::RGate => match params { + [Param::Float(theta), Param::Float(phi)] => { + Some(aview2(&gate_matrix::r_gate(*theta, *phi)).to_owned()) + } + _ => None, + }, Self::CHGate => todo!(), Self::CPhaseGate => todo!(), Self::CSGate => todo!(), @@ -957,7 +962,21 @@ impl Operation for StandardGate { ) }), Self::CRXGate | Self::CRYGate | Self::CRZGate => todo!(), - Self::RGate => todo!(), + Self::RGate => Python::with_gil(|py| -> Option { + let theta_expr = clone_param(¶ms[0], py); + let phi_expr1 = add_param(¶ms[1], -PI2, py); + let phi_expr2 = multiply_param(&phi_expr1, -1.0, py); + let defparams = smallvec![theta_expr, phi_expr1, phi_expr2]; + Some( + CircuitData::from_standard_gates( + py, + 1, + [(Self::UGate, defparams, smallvec![Qubit(0)])], + FLOAT_ZERO, + ) + .expect("Unexpected Qiskit python bug"), + ) + }), Self::CHGate => todo!(), Self::CPhaseGate => todo!(), Self::CSGate => todo!(), @@ -997,6 +1016,16 @@ impl Operation for StandardGate { const FLOAT_ZERO: Param = Param::Float(0.0); +// Return explictly requested copy of `param`, handling +// each variant separately. +fn clone_param(param: &Param, py: Python) -> Param { + match param { + Param::Float(theta) => Param::Float(*theta), + Param::ParameterExpression(theta) => Param::ParameterExpression(theta.clone_ref(py)), + Param::Obj(_) => unreachable!(), + } +} + fn multiply_param(param: &Param, mult: f64, py: Python) -> Param { match param { Param::Float(theta) => Param::Float(*theta * mult), @@ -1004,7 +1033,20 @@ fn multiply_param(param: &Param, mult: f64, py: Python) -> Param { theta .clone_ref(py) .call_method1(py, intern!(py, "__rmul__"), (mult,)) - .expect("Parameter expression for global phase failed"), + .expect("Multiplication of Parameter expression by float failed."), + ), + Param::Obj(_) => unreachable!(), + } +} + +fn add_param(param: &Param, summand: f64, py: Python) -> Param { + match param { + Param::Float(theta) => Param::Float(*theta + summand), + Param::ParameterExpression(theta) => Param::ParameterExpression( + theta + .clone_ref(py) + .call_method1(py, intern!(py, "__add__"), (summand,)) + .expect("Sum of Parameter expression and float failed."), ), Param::Obj(_) => unreachable!(), } diff --git a/qiskit/circuit/library/standard_gates/r.py b/qiskit/circuit/library/standard_gates/r.py index 9d4905e27866..22c30e24bf6a 100644 --- a/qiskit/circuit/library/standard_gates/r.py +++ b/qiskit/circuit/library/standard_gates/r.py @@ -20,6 +20,7 @@ from qiskit.circuit.gate import Gate from qiskit.circuit.quantumregister import QuantumRegister from qiskit.circuit.parameterexpression import ParameterValueType +from qiskit._accelerate.circuit import StandardGate class RGate(Gate): @@ -49,6 +50,8 @@ class RGate(Gate): \end{pmatrix} """ + _standard_gate = StandardGate.RGate + def __init__( self, theta: ParameterValueType, diff --git a/qiskit/circuit/quantumcircuit.py b/qiskit/circuit/quantumcircuit.py index 08bac04c9e6f..de7a2934a464 100644 --- a/qiskit/circuit/quantumcircuit.py +++ b/qiskit/circuit/quantumcircuit.py @@ -4649,9 +4649,7 @@ def r( Returns: A handle to the instructions created. """ - from .library.standard_gates.r import RGate - - return self.append(RGate(theta, phi), [qubit], [], copy=False) + return self._append_standard_gate(StandardGate.RGate, [theta, phi], qargs=[qubit]) def rv( self,